Is average # of cards per hand in BJ 3.2 or 2.7?

Hello Friends,
I need to know the average number of cards per hand for all hands played, regardless of their outcome, in Blackjack. For some reason the number 3.2 keeps nagging at me, but I read in two different places the number 2.7, however both of these authors said for "standing" hands (whatever that means), so I am thinking they are talking about something else.

Does anyone know this?

Thanks,
Steve